In a personal electric cleaning care appliance (hereinafter referred as cleaning care appliance), a resonance oscillation driving system is frequently used to drive the cleaning care appliance for a rotary motion. As described in the applicant's another patent application PCT/CN2015/071696, the cleaning care appliance comprises a handle with a handle housing. The handle housing is equipped internally with a power supply portion for supplying power to various parts of the cleaning care appliance, a control portion for controlling various operation modes of the cleaning care appliance and turning on or off of the cleaning care appliance, a trigger portion for turning on or off the operation of the cleaning care appliance, and a driver for converting the input electrical energy into mechanical energy output. The driver comprises a transducer, a drive coil, and an iron core of the drive coil located in the drive coil.
FIG. 1 is a schematic diagram of an existing driver. As shown in FIG. 1, when an alternating current i flows through the drive coil, the permanent magnets distributed on the transducer are subjected to a reaction force of the electromagnetic force to drive the transducer to make a reciprocating rotary motion at the frequency of the alternating current, so as to bring the cleaning element carrier and the cleaning elements assembled on the drive shaft of the transducer to perform a reciprocating rotary motion, thus obtaining a cleaning effect. In the above structure, the transducer, the cleaning element carrier and the cleaning elements have natural frequency fn, and the current in the drive coil has its driving frequency f0. The fn is very close to the f0. Generally, if the condition 0.85f0<fn<1.05f0 is satisfied, the electromagnetic force between the drive coil and the transducer could enables the transducer, the cleaning element carrier and the cleaning elements to be in a resonance oscillation state, as a result, a higher mechanical efficiency can be achieved.
An actuator system of the resonance oscillation utilizing magnetic effect for an electric toothbrush is disclosed in the invention patent application of publication NO. CN 103140190 A, which comprises an induction windings located adjacent to the coil windings, the motion of the permanent magnet component generates magnetic flux which induces a voltage in the induction windings according to the position of the induction coils with respect to the permanent magnets. Such an actuator system further comprises a control component, the control component is used to process voltage signals from the induction windings to resolve the voltage generated only by the magnetic flux from the permanent magnet component and is used to compare the voltage with a standard value, and then the comparison value is used to change the frequency or duty cycle of the driving signal, so that the spindle stroke has the desirable magnitude and/or angle. However, neither of these two disclosed documents relates to the specific structure of the circuit, the control mode, and problems such as how to improve the circuit efficiency.
In existing personal electric cleaning care appliances, the electrical energy is converted into mechanical energy by means of the drive coil. To improve cleaning effects, the cleaning elements are usually required to possess rotary motions of different motion amplitudes, so as to meet different requirements of the user. In one prior art, by regulating the current frequency of the drive coil, the frequency of the electromagnetic force between the drive coil and the transducer is made even far away from the natural frequency of the transducer, the cleaning element carrier and the cleaning elements, thus reducing the amplitude of the rotary motion of the cleaning elements. However, this method increases the current of the drive coil, so that the overall power consumption of the cleaning care appliance is increased and the output mechanical power becomes lower. In another prior art, the mean current flowing through the drive coil is decreased by controlling the time during which the current flows through the drive coil, for example, the current in the drive coil is frequently switched using a PWM (pulse-width modulation) mode. The smaller mean current in the drive coil can reduce the motion amplitude of the cleaning elements. This method can obtain a smaller motion amplitude of the cleaning elements while reducing the overall power consumption, however, frequently on-off of the current in the drive coil may cause electromagnetic interference and thus pollution of the environment. It is certainly that an electromagnetic interference can be shielded by other means, but it will increase the cost.